Hydraulic fracturing uses a large volume of water that is selected for its chemical properties. The demand for this type of well services has increased over the past decade, especially because of its successful application for difficult conditions. Horizontal wells are often standard, requiring as much as 4.2 million gallons of water per well in as many as 6 to 9 fracture stages. Because of environmental concerns and fresh water availability, salt water and the flowback and produced water are collected and used for subsequent fracture treatments.
Scale formation due to seawater injection into an oilfield reservoir often causes significant impairment to production. In some cases, sulfate reduction plants are used for example using membrane technologies/reverse osmosis, which can be economically expensive. For cases where seawater is used as a base liquid during stimulation operations, installing a sulfate removal plant can be uneconomical.
Various different methods can be applied to reduce water salinity and to prevent bacteria growth and reduce operational expenses related to corrosion prevention, remediation of corrosion effects, and remediation of emulsion-like produced fluids. Historically, removing sulfate is performed by using a membrane (or other filtration techniques) to filter out the sulfate molecules whereby the feed seawater are partially desalinated. Also, previous methods remove the sulfate ions through filtering technologies, rather than through precipitating out unwanted metal ions by reacting it with non metal ions. While some solutions are technically feasible, the economics and operational requirements are quite costly. A simple, cheap, and highly efficient technology to remove sulfate from a stream of saline liquid that is compatible with other fluid additives and that is easily transportable is needed.